A brief introduction to Git as presented by Greg Lonnon at the January meetup of the Boise Web Technologies Group.

1. Git Intro

4. usage

7. Common starting points

9. SCM Evolution tar/zip RCS SVN CVS clearcase perforce git/hg/bazaar

11. peer to peer architecture

15. Ported to Windows, OSX, any posix based OS

16. Many GUI clients

19. Database theory

20. Graph theory

21. Set theory

23. keys are 20 byte arrays.

25. trees : directories

26. commit : points to a tree, and other commits

27. tag : points to a commit

28. Git: blobs #include <stdio.h> int main() { printf(“hello world”); return 0; } Blobs: files (text and binary), symlinks

29. git: tree permission object hash name 100644 blob 82354a1... README 100755 blob 02342c5... a.out 040000 tree a67ef32... 02342c... src Trees: aka directories

30. git: commit date author parents comment tree Mon Dec 20 16:10:41 2010 -0700 joe developer <joe@gmail.com> 234ab23... Fixed the border defect 89023a2...

31. git: tag date tagger Mon Dec 20 16:10:41 2010 -0700 joe developer <joe@gmail.com> 234ab23... commit comment Release 1.0

32. git: repo git init echo “hello” > B1 git add B1 git commit echo “world” > B2 git add B2 git commit git init echo “hello” > B1 git add B1 git commit mkdir T2 git mv B1 B2 T2 cp T2/B1 B3 git add B3 git commit Time C3 C1 C2 T1 B2 B1 T1 T2 B2 B1 T1 B1 C3 C1 C2 T2 B2 B1 T3 T2 B2 B1 T1 B1

33. git: repo C3 C1 C2 T1 T1 T1 B1 C3 C1 C2 T2 B2 T3 T1 B1

36. tags : immutable (V1.0) C1 C1 C1 C2 C1 C3 C1 C6 C1 C8 C4 C5 C7 master work_br V1.0

37. git: DAG HEAD git init git commit C1 C1 master

38. git: DAG HEAD git branch work_br C1 C1 master work_br

39. git: DAG HEAD git commit C1 C1 C1 C2 master work_br

40. git: DAG HEAD git commit C1 C1 C1 C2 C1 C3 master work_br

41. git: DAG HEAD git checkout work_br git commit C1 C1 C1 C2 C1 C3 C4 master work_br

42. git: DAG HEAD git commit C1 C1 C1 C2 C1 C3 C4 C5 master work_br

43. git: DAG HEAD git checkout master git merge work_br C1 C1 C1 C2 C1 C3 C1 C6 C4 C5 master work_br

44. git: DAG HEAD git checkout work_br git commit C1 C1 C1 C2 C1 C3 C1 C6 C4 C5 C7 master work_br

45. git: DAG HEAD git checkout master git commit C1 C1 C1 C2 C1 C3 C1 C6 C1 C8 C4 C5 C7 master work_br

49. HEAD : current checkout hash

50. git clone HEAD http:/github.com/<user>/<repo> origin git clone http://github.com/ <user>/<repo> local git clone copies the remote objects/references to a new repository The remote repo is nicknamed origin , a remote tracking branch is created to track origin/master local C1 C1 C2 C1 C3 C4 C5 master work_br C1 C1 C2 C1 C3 C4 C5 origin/master origin/work_br master

51. git fetch HEAD HEAD git fetch origin origin local local Fetch moves C6 commit objects to the local repo, and updates the tracking branch origin/master C1 C2 C3 C4 C5 master work_br C6 C1 C2 C3 C4 C5 origin/master work_br C1 C2 C3 C4 C5 origin/master work_br C6 C7 master master origin/work_br origin/work_br

52. git push git push origin origin Push local to origin. The local work_br is a proper superset of the origin work_br branch, and the origin is updated. The local master push fails, it is NOT a not a proper superset of the origin master branch origin HEAD local C1 C2 C3 C4 C5 master work_br C6 C1 C2 C3 C4 C5 master work_br C6 C7 C1 C2 C3 C4 C5 origin/master work_br C6 C7 master origin/work_br

55. git merge HEAD git merge work_br HEAD Merges 1 or more branch into the current branch. C1 C1 C1 C2 C1 C3 C4 C5 master work_br C1 C1 C1 C2 C1 C3 C1 C6 C4 C5 master work_br

56. git merge --squash HEAD git merge --squash work_br HEAD Merges a branch, but does not track the merge. Useful in large repositories with a lot of activity. C1 C1 C1 C2 C1 C3 C4 C5 master work_br C1 C1 C1 C2 C1 C3 C1 C6 C4 C5 master work_br

57. git cherry-pick HEAD git cherry-pick C5 HEAD Calculates and applies the file changes of a commit. Useful for moving changes between a release branch and main development C1 C1 C1 C2 C1 C3 C4 C5 master work_br C1 C1 C1 C2 C1 C3 C4 C5 work_br C5' master

58. git rebase HEAD git rebase master HEAD Moves a “family” of commits to a new “base” Useful for developers to “refresh” their branch. C1 C1 C1 C2 C1 C3 C4 C5 master work_br C1 C1 C1 C2 C1 C3 C4 C5 master work_br C4' C5'

59. git rebase: a closer look HEAD Step 1: Apply d1 to C3 Step 2: Apply d2 to C4' C1 C1 C1 C2 C1 C3 C4 C5 master work_br C4' C5' d1 d2 d1 d2

62. Stable API

63. Use them for scripting git

64. 100+ commands...

65. gitk

66. git gui

68. Use commits to separate out features, debug, temporary work, etc...

69. git != svn, don't treat it like svn...